灌浆充实调节剂对大穗型水稻弱势籽粒灌浆的调控效应

Regulatory Effects of Two Grain Filling Regulators on Inferior Spikelets Filling of Large Panicle Rice

为探究2种灌浆充实调节剂对大穗型水稻品种弱势籽粒灌浆充实的影响及其作用机制,采用大田试验,以大穗型水稻品种交源优216为试验材料,研究了抽穗开花期喷施灌浆充实调节剂(禾立丰和新美洲星)对水稻弱势籽粒灌浆充实、内源激素含量、灌浆充实相关miRNA及其靶基因、编码灌浆充实相关蛋白和蔗糖-淀粉代谢关键酶基因表达量的影响。结果表明,2种灌浆充实调节剂禾立丰和新美洲星显著提高了交源优216的产量、弱势籽粒千粒质量、灌浆速率及灌浆起始势,弱势籽粒千粒质量与对照(清水处理)相比分别提高了16.07%和15.89%;且弱势籽粒中IAA含量在花后9,15,21 d显著增加,Z+ZR含量在花后9,21 d显著增加。禾立丰处理下,弱势籽粒中负调控籽粒灌浆充实的miR167a-c、miR167d-j和miR1432在花后6 d显著下调,编码14-3-3蛋白的基因OsGF14b和OsGF14f在花后12 d显著下调;而正调控籽粒灌浆充实的类萌发素蛋白基因OsGLP3在花后6 d显著上调,蔗糖-淀粉代谢关键酶基因在花后6,12 d显著上调。新美洲星处理下,弱势籽粒中负调控籽粒灌浆充实的miR167a-c、miR167d-j、miR1432在花后6 d显著下调,编码14-3-3蛋白基因OsGF14b和OsGF14f在花后12 d显著下调;正调控籽粒灌浆充实的OsGLP3和蔗糖-淀粉代谢关键酶基因的表达量在花后6,12 d显著上调。相关分析结果表明,弱势籽粒灌浆速率与miR1432、OsGF14f的表达量呈显著负相关关系,而与IAA含量呈显著正相关关系。因此,禾立丰和新美洲星可能是通过调节灌浆前中期灌浆充实相关miRNA及靶基因、编码灌浆充实相关蛋白和蔗糖-淀粉代谢关键酶基因的表达量,进而提高激素IAA和Z+ZR含量,促进弱势籽粒灌浆充实。

In order to explore the effects and mechanism of grain filling regulators on inferior spikelets filling of large panicle rice varieties,large panicle rice variety Jiaoyuanyou 216 was selected as material and an open field experiment was conducted by spraying exogenous grain filling regulators(Helifeng and Xinmeizhouxing)at heading stage.Meanwhile,endogenous hormone contents,expressions of filling-related miRNAs and their targets,and genes encoding filling-related proteins and sucrose-starch metabolism key enzymes were measured.The results should that the two grain filling regulators of Helifeng and Xinmeizhouxing significantly increased the yield of Jiaoyuanyou 216,the 1000-grain weight,filling rate and initial grain filling potential of inferior spikelets.Specifically,compared with the control(spraying water),the 1000-grain weight of inferior spikelets increased by 16.07%and 15.89%,respectively.Content of IAA in inferior spikelets increased significantly at 9,15,21 d after flowering,and the content of Z+ZR increased significantly at 9,21 d after flowering.Under Helifeng treatment,expressions of miR167a-c,miR167d-j and miR1432 were significantly down-regulated at 6 d after flowering,OsGF14b and OsGF14f were significantly down-regulated at 12 after flowering.What′s more,expression of OsGLP3,a gene encoding germin-like protein was significantly up-regulated at 6 d after flowering,and expressions of sucrose-starch metabolism key enzyme related genes were significantly up-regulated at 6,12 d after flowering.However,under Xinmeizhouxing treatment,expressions of miR167a-c,miR167d-j,miR1432 were significantly down-regulated at 6 d after flowering,and expressions of OsGF14b and OsGF14f were significantly down-regulated at 12 d after flowering.More importantly,expressions of OsGLP3 and sucrose-starch metabolism key enzyme related genes were significantly up-regulated at 6,12 d after flowering.Correlation analysis results showed that the filling rate of inferior spikelets was significantly negatively correlated with the expression of miR1432 and OsGF14f,while was significantly positively correlated with the content of IAA.Therefore,Helifeng and Xinmeizhouxing may regulate the expressions of filling-related miRNAs and their targets,as well as the genes of filling-related proteins and sucrose-starch metabolism key enzymes in the pre-and mid-filling period and increase the content of IAA and Z+ZR to promote inferior spikelets filling.